SVT and Flecainide

Posted by guardrail65 @guardrail65, Aug 21 10:49am

I had SVT in 2023 followed by heart ablation for SVT and 2 A-Flutters. I’ve had 2 more SVT’s in 5 days last week. Cardiologist updated Metoprolol to 75mg 2x daily. Heart rate slowed down to normal 60’s at resting. Now heart surgeon wants to add Flecainide for 7 days then an EKG after 7 days. I read all side effects of Flecainide and it actually scares me (which I never get scared about meds but this one I do). I.E. Possibility of death, slows heart arrhythmia, new or worsening irregular heartbeats, chest pain or tightness, difficulty breathing and much more… I have oxygen levels averaging 75-85 when off oxygen and already have trouble breathing. So, will this drug cause even more now that oxygen and Metoprolol is working or is electro physio part of it supposed to do something additional that Metoprolol can’t?

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gloaming | @gloaming | Aug 22 2:31am

Flecainide is tolerated by many users, but some simply cannot tolerate it. Also, it's contraindicated for people with diagnosed heart failure. You don't mention HF as part of your 'suite', so that is why flecainide is being offered.

I don't know what else about your case would suggest flecainide as a trial, but your cardiologist must have an idea. I would ask that person what gives.

Metoprolol is not an anti-arrhythmic drug. It does HELP with arrhythmias, but it's purpose is twofold: to slow the heart's rate when it is fibrillating or fluttering, and also to reduce the force of each contraction so that the thumps and bumps are not truly objectionable and interfere with your well-being.

If the flecainide works, and keeps you in NSR for lengthy periods, then your sats (saturation) of oxygen should be optimal. It is when your heart is experiencing an arrhythmia that your O2 should fall as a likelihood. If it drops on flecainide, make sure your cardiologist learns of it....right away.

labexperiment | @labexperiment | Aug 23 8:27am

Metropolol is a beta blocker meaning it lessens sympathetic response by blocking or slowing down beta andregenic nerve fiber condustion. It does nothing to the atria but is specific to the AV node and blocks electrical impulses so the ventricles aren't beating at hte atrial rate. Flecanide acts by blocking the Nav1.5 sodium channels of the heart. This increases the duration of the cardiac action potential, thereby slowing the electrical conduction of the heart and reduces the contractility of the muscle. The effect of flecanide is heart rate-dependent and increases as heart rate increases.

ellanz | @ellanz | Aug 27 8:17pm

I was prescribed flecainide 4 weeks ago following an unsuccessful SVT ablation attempt. Before that, I'd been on diltiazem, a calcium channel blocker that was prescribed instead of a beta-blocker because I get asthma so can't take BBs. I had read all the flecainide horror stories but was reassured by the EP. For the first week following the unsuccessful ablation, I just took flecainde, 100mg daily. My chest felt tight occassionally during that period so he added diltiazem back in, 120 mgs. That's been great. All my previous SVT symptoms have gone and the chest tightness. Before the ablation attempt, I'd been on 240mg diltiazem daily for a couple of months but was still getting the occasional breakthrough that made me very lightheaded. That higer doseage of diltiazem also made me a bit lethargic, I found it harder to get fitter when I was exercising, and I felt like I was bit brain-fogged. I'm really happy with how the current combo is working for me. Have much more energy, felling fitter and sharper.